# Homework Help: Torsion pendulum

1. Dec 2, 2011

### queenstudy

1. The problem statement, all variables and given/known data

i did my experiment on torsion pendulum and there is a graph that i am supposed to draw ( C as a function of 1/L) where C is the tosion constant and L the length of the wire after that they give me a formula C=1/32L *∏*G*a^4 where G is called the modulus of rigidity and a is the diameter of the wire my purpose is to find G

2. Relevant equations
1) i just want to know the expected result of G because i got 300 Pa??
2) how to find the uncertainty of G ?
3) the unit of G is Pa right??

3. The attempt at a solution i did the graph where i am supposed to make the uncertainty rectangles but the graph didnt work out too much for me especially that i repeated the experiment several times and i have the same answers ( with a small difference) so any suggestions

2. Dec 3, 2011

### Spinnor

It looks like yes to 3 but typical numbers for metal are 10's of giga Pa, 10E9 Pa see,

http://www.engineeringtoolbox.com/modulus-rigidity-d_946.html

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